Rear End Oil

[1Nebel0]

I have a 2007 one ton duallie and will be putting a higher capacity cover on. The dealer wants $27. 95 a quart which is rediculous... I want to use Amsoil 75-90 oil. . do I need to add the modifier or is the syn enough. The truck has posi rear end. . The dealer said their fluid doesn't need the modifier... I have little confidence in counter people and put my faith in this forum. I will use what ever the group feels is good oil... just don't want to buy the OEM oil(8 quarts) at $27. 95 a quart ever 15,000 miles. Thanks for all the great insights always... Steve. .

 

[Jim W]

I bought 8 quarts of 75W-90 Amsiol for my rear diff with my Mag-Hytec cover when installed. I did not need nor do you need any modifiers in the oil. Do a search on this site for your question, a lot of answers out there telling you no. There are two dealer tech's on this site and they will tell you that the modifiers are not required either.

I believe the O and M guide also tells you not to use any modifiers in the diff oil.

Check the poll on this site for diff fluid also.

 

[mberry]

Steve,

In my opinion the 15K change interval for the diff(s) is far too short. It may be correct for the stock Mopar fluid, but since you are switching over to Amsoil I wouldn't think of changing it until at least 30K miles. I run Amsoil 75W-90 and it works well for me at 30K changes with the stock covers. No modifier needed. Also, if you do tow heavy and often, I would personally opt for the 75W-110 Amsoil. Again, my opinion and this is what I do on my truck. Hope this helps.

Mark

 

[WRStrong]

I used Amsoil in my 2003 2500 w/ anti-spin axle. Developed a slight shudder on take off after going to Amsoil. Added the Amsoil friction modifier and it stopped. Just my 2 cents. Maybe a fluke. I'd say run it without and if there's no problem - don't add modifier.